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I'm 99% positive that the loose lugs are attributable to operator error and not some engineering anomaly. Especially given that almost all of them were loose (to a degree).
Torque in the morning. Torque after lunch. You'll be fine.
Wheel studs are a wear item. Lugs almost never wear out. Both hold the wheel to the hub.
Darn, now I have to go look for markings on my bolts take them out , clean everything, buy some moli , coat the threads to depth, coat the head to mating cap ring surface and Not wheel to cap ring surface, insert bolt finger tight, torque 1/3, then 2/3, then full torque.
**** , I'm never going to get this thing out for a drive
Darn, now I have to go look for markings on my bolts take them out , clean everything, buy some moli , coat the threads to depth, coat the head to mating cap ring surface and Not wheel to cap ring surface, insert bolt finger tight, torque 1/3, then 2/3, then full torque.
**** , I'm never going to get this thing out for a drive
Hahahaha the amount of detailed info and OCD in this forum never seizes to amaze and entertain me in equal measure.
Here's what I'm going to do: get my torque wrench calibrated, re-torque to 96 ft lbs, re-check torque in the morning before the next track day, re-check after 5 laps. Then I will re-check before each session.
Not going to use anti-seize, markings or any other gooey substance on my bolts.
If everything goes well, case closed. If not, I will replace them with regular steel bolts.
Here's what I'm going to do: get my torque wrench calibrated, re-torque to 96 ft lbs, re-check torque in the morning before the next track day, re-check after 5 laps. Then I will re-check before each session.
Not going to use anti-seize, markings or any other gooey substance on my bolts.
If everything goes well, case closed. If not, I will replace them with regular steel bolts.
I will update the thread with the final verdict.
Thanks to all for your replies
Why use the outdated 96 ft.lbs. spec when Porsche has released a retroactive update to 118 ft.lbs. They obviously did this for a reason and I bet it had to do with lug bolts loosening under extreme use, like on a track.
Why use the outdated 96 ft.lbs. spec when Porsche has released a retroactive update to 118 ft.lbs. They obviously did this for a reason and I bet it had to do with lug bolts loosening under extreme use, like on a track.
The change is retroactive to 2011 but also a permitted change for the older cars as well. If I had torqued to 96 ft.lbs. and had bolts loosen, I would try the higher setting that is allowed.
Your track day kit should include a torque wrench. We're driving some heavy cars pretty fast and those brakes generate a lot of heat. Just try measuring the temperatures with a laser thermometer! You might be surprised...
I've seen video of F1 brake rotors cycling between hot and glowing red hot several times per lap, but this shows the extremes in temperature on street brakes. It also says that temps at the rotor surface can easily exceed 1,000 deg. F at the track (at about 2:20).
Watching the rotor hat temps, you can see that the brakes do a good job dissipating heat and insulating the rotor from the hat, but even so, there is pretty serious temperature fluctuation at the hat over the course of the video. I point this out because the hat is where the lugs are, and it's the drastic changes in temperature (not the maximum temperature) that contribute to lugs loosening. Plus, of course, the massive forces on them as you go around the track.
Just think about what you do when you have a stuck bolt. What do you do? You apply as much heat as you can as fast as you can, then quench to drop the temperature rapidly. You do this a few times until even the most stuck bolt gives up. Sounds a lot like what happens to your rotors at the track.
I don't race, but it would seem to me that a good torque wrench would be an invaluable tool to have at the track.
Hahahaha the amount of detailed info and OCD in this forum never seizes to amaze and entertain me in equal measure.
Here's what I'm going to do: get my torque wrench calibrated, re-torque to 96 ft lbs, re-check torque in the morning before the next track day, re-check after 5 laps. Then I will re-check before each session.
Not going to use anti-seize, markings or any other gooey substance on my bolts.
If everything goes well, case closed. If not, I will replace them with regular steel bolts.
I will update the thread with the final verdict.
Thanks to all for your replies
Thanks for doing this and reporting back when done. Always good to get more information on these "special topics".
As an aside on track safety - I replace my OEM Porsche wheel bolts about every two track seasons due to the number of repetitive on-off i.e. tighten-loosen cycles (street tires v. track tires) and the extreme heat/cool cycles from track driving. It may be slight overkill, but for me it is a very cheap insurance policy against wheel bolt failure (I have personally witnessed a wheel coming off a GT3 - scary sight). And of course I check and re-check wheel bolt torques throughout the day(s).
^Wheel studs/nuts are consumables and I was told to replace at least every two seasons or more depending on frequency of use.
They should also be inspected regularly for corrosion, and I now know (if I ever use them again) to closely inspect the nuts for corrosion or signs that they are not seating properly.
05-12-2017, 02:46 PM
